托福阅读事实信息题是阅读考试中比较常见的一种题型，tpo则是托福阅读备考最权威的材料，所以托福小编综合二者，为大家集中整理了tpo阅读中考察的事实信息题及其对应的解析，供大家参考使用。本文带来的是TPO16-2的事实信息题，一起来看看吧。
TPO16-2 Planets in Our Solar System
Paragraph 4
Other dimensions along which the two groups differ markedly are density and composition. The densities of the terrestrial planets average about 5 times the density of water, whereas the Jovian planets have densities that average only 1.5 times the density of water. One of the outer planets, Saturn, has a density of only 0.7 that of water, which means that Saturn would float in water. Variations in the composition of the planets are largely responsible for the density differences. █The substances that make up both groups of planets are divided into three groups—gases, rocks, and ices—based on their melting points. █The terrestrial planets are mostly rocks: dense rocky and metallic material, with minor amounts of gases. █The Jovian planets, on the other hand, contain a large percentage of the gases hydrogen and helium, with varying amounts of ices: mostly water, ammonia, and methane ices. █
3. Paragraph 4 mentions which of the following as a reason why terrestrial planets are dense?
A. They are made up of three groups of substances.
B. They are composed mainly of rocky and metallic materials.
C. They contain more ice than Jovian planets.
D. They contain relatively small amounts of water.
解析：以dense做关键词定位至第一句，但这句只是单纯说类地行星比类木行星密度大，没给出原因，正确答案在第三句的density difference，说组成物质的不同导致两者密度的差异，所以答案是B，主要由金属和岩石构成。A不是原因C说反D没说
【4】两类行星其它方面的区别中，比较显著的是密度和构成成分。类地行星的平均密度大约为水的5倍，而类木行星的平均密度大概只有水的1.5倍。外行星中土星的密度只有水的0.7倍，也就是说土星可以浮在水上。行星的构成成分不同很大程度上是因为密度差异。两类行星的构成物质根据熔点可以划分为三类——气体、岩石和冰。类地行星多数由岩石(致密岩石和金属材料)以及少量气体构成。而类木行星恰恰相反，包含较大比例的气态氢和氦，以及各种形态的冰(大部分是水、氨和甲烷冰)。
Paragraph 5
The Jovian planets have very thick atmospheres consisting of varying amounts of hydrogen, helium, methane, and ammonia. By comparison, the terrestrial planets have meager atmospheres at best. A planet's ability to retain an atmosphere depends on its temperature and mass. Simply stated, a gas molecule can "evaporate" from a planet if it reaches a speed known as the escape velocity. For Earth, this velocity is 11 kilometers per second. Any material, including a rocket, must reach this speed before it can leave Earth and go into space. The Jovian planets, because of their greater masses and thus higher surface gravities, have higher escape velocities (21-60 kilometers per second) than the terrestrial planets. Consequently, it is more difficult for gases to "evaporate" from them. Also, because the molecular motion of a gas depends on temperature, at the low temperatures of the Jovian planets even the lightest gases are unlikely to acquire the speed needed to escape. On the other hand, a comparatively warm body with a small surface gravity, like Earth's moon, is unable to hold even the heaviest gas and thus lacks an atmosphere. The slightly larger terrestrial planets Earth, Venus, and Mars retain some heavy gases like carbon dioxide, but even their atmospheres make up only an infinitesimally small portion of their total mass.
6. According to paragraph 5. which of the following statements is true of both Jovian and terrestrial planets?
A. The thicker the atmosphere, the smaller the planet's mass
B. The more varied the gases in the atmosphere, the higher the temperature
C. The higher the surface gravity, the higher the escape velocity
D. The less the atmosphere contributes to the total mass, the lower the temperature
解析：因为同时问到两种星星，所以不能单独找任何一种，接着刚才的题往下看，说行星保持大气的能力取决于其温度和体积，下面分述了体积越大，温度越低，气体越难以逃离，也就是逃逸速度越大，大气层越厚。所以A和D说反，B没说，答案是C。正选不会的话可以用排除法
【5】类木行星有非常致密的大气层，主要由变化量的氢、氦、甲烷和氨组成。相比之下，类地行星的大气层则要稀薄得多。一个行星保持大气的能力取决于其温度和质量。简单来说，如果气体达到逃逸速度，那么气体分子可以从行星上“蒸发”。地球的逃逸速度大约为11千米/秒。任何物质，包括火箭，要离开地球进入太空就必须达到这个速度。由于类木行星的质量较大并因此产生更高的表面引力，因此，类木行星的逃逸速度(21～60千米/秒)要比类地行星高得多。所以，气体从类木行星的表面“蒸发”就更为困难。同时又因为气体分子运动取决于温度，所以在类木行星这样的低温环境下，即使是最轻的气体也无法达到所需要的逃逸速度。而从另一个角度讲，一个相对温暖表面引力很小的天体，比如月球，甚至无法留住最重的气体，因此没有大气层。体积稍大的类地行星，比如地球、金星和火星，保持了二氧化碳等一部分较重的气体，但即便如此，大气构成也只占它们总质量的很小一部分。
7. According to paragraph 5, what is a major reason that Jovian planets have much thicker atmospheres than terrestrial planets do?
A. Jovian planets have lower surface gravities.
B. Jovian planets have lower temperatures.
C. Jovian planets have lower escape velocities.
D. Jovian planets' gas molecules have higher average speeds.
解析：接上题，类木行星体积大，温度低，引力大，逃逸速度大，所以A和C说反;B正确。原文倒数第三句说气体分子的运动速度取决于温度，温度越低，分子的运动速度越小，所以D和B事实上是反的，所以D也说反了
【5】类木行星有非常致密的大气层，主要由变化量的氢、氦、甲烷和氨组成。相比之下，类地行星的大气层则要稀薄得多。一个行星保持大气的能力取决于其温度和质量。简单来说，如果气体达到逃逸速度，那么气体分子可以从行星上“蒸发”。地球的逃逸速度大约为11千米/秒。任何物质，包括火箭，要离开地球进入太空就必须达到这个速度。由于类木行星的质量较大并因此产生更高的表面引力，因此，类木行星的逃逸速度(21～60千米/秒)要比类地行星高得多。所以，气体从类木行星的表面“蒸发”就更为困难。同时又因为气体分子运动取决于温度，所以在类木行星这样的低温环境下，即使是最轻的气体也无法达到所需要的逃逸速度。而从另一个角度讲，一个相对温暖表面引力很小的天体，比如月球，甚至无法留住最重的气体，因此没有大气层。体积稍大的类地行星，比如地球、金星和火星，保持了二氧化碳等一部分较重的气体，但即便如此，大气构成也只占它们总质量的很小一部分。
8. Paragraph 5 supports which of the following statements about the ability of planets to retain gases?
A. More-massive planets are less able to retain gases than less-massive ones.
B. Planets are more likely to retain heavy gases than light gases.
C. Jovian planets are unlikely to retain the lightest gases.
D. Only terrestrial planets have been able to retain carbon dioxide.
解析：接上题，类木行星体积大，温度低，引力大，逃逸速度大，更容易有厚的大气层，所以A和C说反了;而D明显不对，所以正确答案是B
【5】类木行星有非常致密的大气层，主要由变化量的氢、氦、甲烷和氨组成。相比之下，类地行星的大气层则要稀薄得多。一个行星保持大气的能力取决于其温度和质量。简单来说，如果气体达到逃逸速度，那么气体分子可以从行星上“蒸发”。地球的逃逸速度大约为11千米/秒。任何物质，包括火箭，要离开地球进入太空就必须达到这个速度。由于类木行星的质量较大并因此产生更高的表面引力，因此，类木行星的逃逸速度(21～60千米/秒)要比类地行星高得多。所以，气体从类木行星的表面“蒸发”就更为困难。同时又因为气体分子运动取决于温度，所以在类木行星这样的低温环境下，即使是最轻的气体也无法达到所需要的逃逸速度。而从另一个角度讲，一个相对温暖表面引力很小的天体，比如月球，甚至无法留住最重的气体，因此没有大气层。体积稍大的类地行星，比如地球、金星和火星，保持了二氧化碳等一部分较重的气体，但即便如此，大气构成也只占它们总质量的很小一部分。
Paragraph 6
The orderly nature of our solar system leads most astronomers to conclude that the planets formed at essentially the same time and from the same material as the Sun. It is hypothesized that the primordial cloud of dust and gas from which all the planets are thought to have condensed had a composition somewhat similar to that of Jupiter. However, unlike Jupiter, the terrestrial planets today are nearly void of light gases and ices. The explanation may be that the terrestrial planets were once much larger and richer in these materials but eventually lost them because of these bodies' relative closeness to the Sun, which meant that their temperatures were relatively high.
11. According to paragraph 6. what is a possible explanation for the lack of light gases and ices on terrestrial planets?
A. The location of terrestrial planets caused them to lose some of the materials they once contained.
B. Terrestrial planets were formed much later than Jovian planets.
C. The composition of terrestrial planets was different from that of Jupiter.
D. Terrestrial planets were formed out of different material than the Sun was.
解析：以lack of gases and ices做关键词定位至倒数第二句，这句话只是单纯说现象，最后一句才是解释，而且这句话刚才已经讲过，说由于距离太阳近，类地行星最终失去了这些气态物质，所以答案是A。其余答案均与本段首句说反
【6】太阳系有序的性质使得大部分天文学家得出结论：行星基本形成于同一时间并且构成物质与太阳相同。天文学家们推测，所有行星原始状态的尘埃和气体形成的云状物凝聚，合成物与木星的有些类似。然而，和木星不同的是，如今类地行星上的轻质气体 和冰极度缺乏。有一种解释认为，类地行星曾经体积更大并且物质构成上更为丰富多样，但因为它们距太阳较近致使温度相对较高而最终失去这些物质。
以上就是托福阅读TPO16-2中的事实信息题及其解析，大家可以在备考的时候参考复习，希望能够帮助大家的考前准备。最后前程百利祝大家都能取得理想的托福考试成绩。
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